Rather Annoying Problem

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A major problem has been that I cannot access some threads. This seems to happen randomly, but a trigger seems to be making a post to that thread. All of a sudden, I cannot view the post; after clicking the link, I just wait and wait until the connection times out. Other posts display fine. The cause of this problem is very mysterious to me as a computer science major with some knowledge of database and Web development.

Some possible causes:

• A moderator has locked the thread. This is not possible because other people have viewed and even responded to the post.
• A moderator has blocked me from the thread. I cannot view the thread even after I log out.
• The session is botched. Logging out and logging back in does not fix the problem. It may persist for days and suddenly go away.
• It has something to do with the cookie or browser cache. I've tried launching another browser to be still unable to access the thread.
• Too many users are trying to view the thread concurrently. This problem can persist for days at a time while other people view and post to the thread.
• The database is distributed, and the thread I am trying to access is on an unresponsive server. This is implausible for a Web forum and does not agree with the fact that other people can access and view such threads.
• My IP address, for whatever reason, is blocked from accessing a particular thread temporarily.
• Other people have reported this problem for various threads.
  

A PHP Web application like this works roughly by accepting an incoming HTTP connection, authenticating the user against the user table of the database, creating a session variable/browser cookie, and sending a query to the backend database to generate the content of the Web application that I will see displayed in my browser. Here comes the part that makes this bug especially odd: Whenever I click a link to view a particular thread, the PHP script receives several relevant pieces of data: my username/ID, the ID number of the thread I wish to view, and the range of posts within the thread I want to view. The application will verify that I have sufficient privileges to view the thread (i.e., I am not trying to view a moderator-only thread). Next, one inordinately complicated SQL query will be submitted to the database, or several separate queries will. The first (sub)query retrieves the list of users I've ignored so that they will be excluded from the final result (I have ignored no one, by the way). The query will select all posts matching the thread ID and within the range specified from the posts table of the database. Another query will turn raw user IDs into the username, post number, avatar image, title, and signature seen alongside each post. After this, the PHP script formats the data into a webpage that is sent to the user's browser for viewing.

Problems can occur along the way, and that's why PHP scripts are thoroughly debugged before being put into widespread use. The most common problem is a lack of responsiveness between the PHP script and the database, but this would affect the entire site and would quickly have the administrator's attention. Most logical problems in the script or query should affect access to all threads rather than one particular thread for one particular person. This is what is so odd about it.

Actually, the connection to the server does not time out. Instead, the browser simply stops with no error message at all. It stays on the currently viewed page without doing anything. It eventually just stops.

I'm having the same problem. It's been especially bad today.

Other threads on the same issue:
http://www.wrongplanet.net/modules.php? ... pic&t=4079
http://www.wrongplanet.net/modules.php? ... pic&t=4006

I had trouble getting into this thread earlier. Has Alex said anything about it? It seems like threads that work reliably are becoming the exception rather than the rule now.

It's driving me nuts too.

The older threads seem fine.
It's just the newer ones with me, and the older threads that have new pages added to them.
I thought it was my computer but sorta glad it's not, if you know what I mean.

I have been experiencing this problem as well. It is not happening with any that are just one page. It seems most common with 2 page threads, but also with a few of the longer ones.

I'm experiencing similiar problems, I would assume it's a site-wide issue.

I've made a post about it in the moderators section, and provided a link to this thread. Hopefully Alex will be more likely to notice it there.

Alex probably botched up the code AGAIN.

Its an annoying problem.

Having said that I'd like to add that Alex and whomever else is helping "behind the scene" do an excellent job most of the time. It must be quite an effort to keep this site up, both in time and money.

I appreciate having this site here and consider the occusional computer mess-up a minor annoying side issue.

BeeBee

Actually, I'd love to see the database schema for this system. I've been able to imagine a great deal of it simply by observing the bugs in action.

This system strongly resembles a system I have running on my Server at home called PHP Nuke. I also have a BBS Plug-in for it, which creates its own tables in addition to the ones you get with PHP Nuke.

It is a problem I deal with too sometimes.

I had the same problem on AFF today and thought it must have been because I have a fairly old computer and it was getting a bit slow.